Abstract
The authors present spectroscopic observations of the nuclear region of NGC 3783 from 1987 to 1989. The data show variations on the intensity of the Balmer lines and continuum and a comparison with published data indicates that the spectrum obtained in May 1988 corresponds to the lowest state of activity so far reported to this galaxy. It has been used to investigate the nuclear stellar population, which is mainly old (>5 Gyr), has solar metallicity, and contributes with 50% of the nuclear light at λ5600 Å in this spectrum. During the period covered by the observations the luminosity of the Hβ line increased by 3.1×1041ergs/s.
